When Donkey Kong 64 released all the way back in 1999, it was the first Nintendo 64 game to require the system’s 8MB Expansion Pak add-on in order to work. Advertising at the time suggested that the game was just so big that it couldn't possibly work without it. However, Chris Marlow, one of the game’s programmers, has confirmed in a recent director’s commentary video (which should only be viewed by mature audiences) for Conker's Bad Fur Day that the Expansion Pak was needed in order to prevent a game-breaking glitch from occurring.

Marlow explains that a glitch would cause the game to randomly crash, but only when configured to work using the N64’s standard 4MB memory setup. As Rare was unable to identify the cause of the crash, it was eventually forced to release the game with the Expansion Pak bundled-in for free.

This naturally came at a great expense to the developer and Nintendo at the time, but former Rare employee Chris Seavor (perhaps best known for providing the voice of Conker) states during the same video that this ended up working in Perfect Dark’s favour (which released a year later), as that game actually did require the Expansion Pak in order for all of its gameplay features to work. Perfect Dark ended up selling more than 3 million copies worldwide.

Was Nintendo and Rare wrong to advertise Donkey Kong 64’s mandatory usage of the Expansion Pak in the way that it did? Share your thoughts on this interesting revelation in the comments section below.